Heretofore, there has been known an automatic transmission (hereafter referred to as AMT (Automated Manual Transmission) that is constructed by attaching respective actuators to an existing manual transmission in a vehicle using an internal combustion engine (engine) as a driving source and that automatically performs a series of gear change operations (disconnection/connection of a clutch, gear shift and select operation) in depending on the driver's wish or the vehicle state. In the control of, for example, the clutch, the AMT performs the control by converting a clutch torque required from the vehicle property into a clutch actuator operation amount being the operation amount of a clutch actuator. The relation between the aforementioned clutch torques and clutch actuator operation amounts is obtained statically from the cushion property or the like of a clutch disc at the time of shipment. However, it has been known that in the vehicle being in use, the relation is influenced greatly by dynamic variable factors such as wear of a clutch facing, change in μ (frictional coefficient) due to heating, aged deterioration and the like.
Like this, as a change occurs in the relation between the clutch torques and the clutch actuator operation amounts, the disconnection operation and the engagement operation of the clutch at the time of a gear change in the case of the AMT becomes unable to be done at the timing as intended. For example, there arises an anxiety that if the disconnection time of the clutch becomes long beyond the time intended, the torque from the engine is not transmitted to wheels during the disconnection of the clutch, thereby making the driver feel a stall. Further, when the disconnection time of the clutch lengthens, the engine with no load imposed thereon picks up excessively, and hence, there arises another anxiety that when the clutch is brought into engagement, an excessive gear change shock is generated due to an increase in the difference between the rotational speed of the engine and the rotational speed of an input shaft of the transmission. For this reason, there has been proposed a technology in which the relation between clutch torques and operation amounts of a clutch actuator is learned appropriately to compensate a clutch torque map defining the relation (Patent Document 1 for example). In the technology disclosed in Patent Document 1, the learning is done at the time of a starting and at the time of a gear change at which the disconnection and engagement operations of a clutch are performed. Particularly, at the time of a starting, the rotational speed of an input shaft of the transmission remains almost zero, so that it is possible to acquire the relation between the clutch torques and the operation amounts of the clutch actuator which are stabilized at all times. Then, the relation between the clutch torques and the operation amounts of the clutch actuator is compensated on the basis of the acquired data, and the disconnection time of the clutch is controlled to become an appropriate time to suppress the generation of a stall feeling, the generation of a gear change shock due to the excessive pick-up of the engine, and the like.